초록 |
Most polymer films have a free surface (surface exposed to the air). Recent studies have emphasized the importance of the free surface in many aspects of polymer processing. We have recently shown that the free surface plays the critical role in controlling the mesogen alignment of side chain liquid crystalline polymers (SCLCPs).1 A skin layer (typically 20 nm thickness) or inkjet-printed pattern at the free surface is able to regulate the mesogen orientation of SCLCP films of micrometers thickness.2,3 The mesogen orientation can be switched by the photoresponsive top surface both in the in-plane2 and out-of-plane3 directions. Another interesting aspect is the surface effect for the induction of surface morphing.4 Surface relief grating formation could be performed also for a light-inert SCLCP films with a photoresponsive surface skin layer.5 (1) T. Seki, Bull. Chem. Soc. Jpn., 91, 1026 (2018); T. Seki, Polym. J., 46, 751 (2014); T. Seki, Macromol. Rapid Commun., 35, 271 (2014). (2) K. Fukuhara et al., Nat. Commun., 5, 3320 (2014). (3) T. Nakai et al., Langmuir, 32, 909 (2016). (4) I. Kitamura et al., Sci. Rep., 9, 2556 (2019). (5) I. Kitamura et al., Sci. Rep., 10, 12664 (2020). |